Notes

above are for ghost before 2.0 version.
for latest ghost, version 2.0,
The folder for new app should be "Ghost/core/server/web/newapp"
The hacked core js is Ghost/core/server/web/parent-app.js
The code for add route is same as above.
Please be sure that your new route is add before blog's route.
Otherwise, you will got 404 error.